This invention relates to the tremolo device for stringed musical instruments.
Tremolo devices for stringed instruments are widely used, particularly for electric guitars. The tremolo is operable for providing impressive acoustic effects by simultaneously increasing or decreasing the tension of all strings of a stringed instrument.
FIG. 14 shows a conventional tremolo device 120, installed on a body B of a stringed instrument, here a guitar. The tremolo is comprised of a tremolo body which serves as a guitar (bridge) 130 on which there is a string support 131 including a bridge saddle, etc. for the support of the guitar strings S. The string support 131 is arranged at the top surface of the body, while a tremolo block 132 protrudes below the top surface. A spring 140 maintains a state of equilibrium of the tremolo body 130 by working together with an arm 135 for manipulating the swinging of the tremolo body 130 installed on the surface of the instrument and the guitar string S that is spaced above the surface of the body B as the spring extends between the tremolo block 132 and the body B.
The tremolo body 130 remains at a location and orientation at which there is a balance between the tensile forces exerted by all of the strings S and the force of the spring 140 that works in the opposite direction for maintaining a state of equilibrium. As the tremolo body 130 is swung by moving the arm 135, the tension of all the strings S is simultaneously either increased or decreased, causing the musical intervals of the various strings S to either rise or drop. The tremolo body 130 returns to its original equilibrium position when the arm 135 is released. The musical intervals of the strings S are restored to the original intervals as the state of equilibrium is restored.
However, a balancing system for a tremolo body 130, which is based on the force of the spring 140 and on the tensile strength of the strings S, is extremely sensitive. Its tuning becomes out of order if the tremolo body 130 is not completely restored to its original state of equilibrium (which position in a balanced state serves as the central point) after the swinging of the tremolo body 130 due to such factors as friction at the swaying fulcrum of the tremolo body 130, the incompleteness of the restoring force of the spring 140, a performer""s hand touching the tremolo body 130 or the arm 135 during a performance, choking (bending of the string) or fluttering (blurring of sound due to the moment of inertia that is produced at the time when the hand is suddenly taken away from the arm 135), or the mutilation of a string S.
Another major shortcoming of this tremolo device 120 is that tuning it is extremely difficult, because when tuning is performed until a certain string is raised to its target interval, the sum of the tensions of all of the strings S also increases. This moves the position of the state of equilibrium of the tremolo body 130 in the direction toward the neck of the guitar to the front, shortening the distance from the nut of the guitar to the string support part of the tremolo body, thereby reducing the tension of the other strings S, in turn causing the intervals of the other strings to decrease. Conversely, when the tension of some string S is lowered, the musical intervals of other strings S increases. Accordingly, it is theoretically impossible to completely and perfectly tune all of the strings S, and it requires an extremely large effort to bring the strings near to a perfectly tuned state.
For each string S there is a prescribed relationship among the target intervals, string density and the length of the string. Where one terminal end of the string S moves like the tremolo device 120 having a conventional structure, there are numerous neutral points that strike the balance in the tuning of the open strings, except for the scale length of the conventional stringed instruments, depending upon the strength of the spring 140. Accordingly, the desired musical intervals cannot be obtained if a state of equilibrium is achieved in front or at the back of the design location of the state of equilibrium (neutral point), even when the fretting on the guitar neck may be controlled.
There has been great interest in overcoming the above described shortcomings of the tremolo device 120. Recently, many tremolo devices employing a string which is stronger than the tensile force of known strings have been proposed, as described in Toku Kai Hei 1-93793 and Toku Ko Hei 2-48120, etc.
The mechanism described in Toku Kai Hei 1-93793, however, requires applying an extremely strong force for operating the tremolo arm when the musical intervals are to be raised through an increase in the tensile force of the string.
In the tremolo device in Toku Kai Hei 2-48120, on the other hand, the restoring force of the spring may be affected because the spring is tilted or deformed in a direction other than its direction of expansion or contraction when the tremolo body is swung, as the tremolo block and the spring are directly connected to each other. Moreover, in this tremolo device, the sound created at contact between a stopper and the tremolo body for stopping the tremolo body is quite large. When a buffer member, e.g. of rubber, etc. is interposed between the two elements to control the sound, the small size of the contact area contributes toward increasing the amount of the deformation of the buffer member and produces erroneous tuning.
In addition, this tremolo device has many places requiring adjustment. It is difficult for the user to determine locations requiring adjustment and the appropriate method for such adjustment.
This invention was directed toward the above described circumstances. Its purpose is to provide a tremolo device for the stringed instruments, which is capable of minimizing erroneous tuning, making it possible to easily and accurately carry out tuning, and to reduce the contact sound produced when the tremolo body is swung, and where the number of the locations requiring adjustment is small.
The invention relates to a tremolo for a stringed instrument, constructed to obtain musical intervals by changing the tension of a string of the instrument through the swinging of the tremolo body based on the operation of an arm. A tremolo body is installed on the body of the stringed instrument to swing freely, with a string support for the support of the string being arranged on the top surface and a tremolo block protruding toward the bottom side. An arm installed on the tremolo body is operated to manipulate the swinging of the tremolo body. A reverse side mechanism base is arranged below said body. A positioning stopper is provided at the bottom of the base or body. A slide block is constructed to be able to move freely to the front or to the rear. A movable stopper is movable back and forth freely and is capable of contacting or mi moving away from the slide block. A link links the tremolo block and the slide block.
A first spring between the bottom side mechanism base and the slide block urges the slide block toward the front. A second spring between the movable stopper and the bottom side mechanism base also urges the movable stopper to the front. When the tremolo arm is not being operated, the slide block and the movable stopper contact and the movable stopper and the positioning stopper contact due to the tensile strength of the string disposed above the body. The forces of the first and second springs bring the tremolo body into a state of equilibrium.
When the tremolo body is swung to tilt toward the front by operating the arm, the tremolo block is rotated to the rear. As a result, the slide block and the movable stopper slide rearward joined by the link. When the movable stopper has been separated from the positioning stopper, and while the operation of the tremolo arm has been discontinued, the slide block and the movable stopper are restored to their original positions where the movable stopper contacts the positioning stopper due to the urging strength of the first spring and the second spring. This brings the tremolo body into a state of equilibrium.
When the tremolo body is swung to tilt rearward by the operation of the tremolo arm, the tremolo block rotates to the front, which slides the slide block to the front through the link. That separates the slide block from the movable stopper. When operation of the tremolo arm has been discontinued, the slide block is returned to its original position touching the movable stopper by the tensile force of the string, thereby restoring the tremolo body to the state of equilibrium.
An axial slide is provided between a first bearing and a second bearing on the bottom side mechanism base. The slide block and the movable stopper are movable freely back and forth along the axial slide. The positioning stopper is provided between the first bearing and the second bearing at the rear or bottom of the base.
The movable stopper has a front which can either touch or move away from the slide block and has a rear which can touch or move away from the positioning stopper.
The second spring is provided between the front of the movable stopper and the second bearing.
The first spring is provided between the first spring front side installation block that has been provided on the front end of the bottom side mechanism base and the first spring rear-side installation block provided on the slide block.
The rotation fulcrum for the tremolo block and the link are positioned approximately right under the swing axis of the tremolo body.
The first spring front side installation block is installed such that its position may be adjusted with respect to the bottom side mechanism base.
A buffer is interposed between the slide block and the movable stopper. A buffer is also interposed between the movable stopper and the positioning stopper.
The link between the tremolo block and the slide block is capable of expansion and contraction.
The action direction of the forces of both the first spring and the second spring is opposite to the direction of the tensile force of the strings. The spring force of the first spring is smaller than the total tensile force of the string, while the sum of the spring forces of the first spring and the second spring is greater than the total tensile force of the string, for achieving equilibrium no matter whether the tremolo body is raised or lowered.
An engagement mechanism, which is capable of being engaged or disengaged, is provided between the slide block and movable stopper. The slide block and the movable stopper are engaged by the engagement mechanism, thereby regulating the movement of the slide block to the front.